This hat encourages good behaviour: improving posts. This is exactly what a good badge should do.

Why not make it a permanent bronze badge? There is an existing badge to encourage people to edit at all, but this one would encourage users to put in enough effort that the post is actually improved.

It should only be awardable once. Making it awardable multiple times would lead to some annoying gaming (such as sniping edits on posts you recognize as good) and would need higher requirements.

There is a year-old badge request for editing a negatively-scored post which later gets a positive score, but I think the hat's criteria is a better choice. The negatively-scored posts that need the most help are probably below -2, and even with a good edit you'll need quite a bit of luck to bring it back over 0.

There are also a lot of very meh-quality posts with a score around 1–3 (particularly given the new review queue) which a good edit could improve enough to gain four more votes, but this behaviour would not be incentivised by the existing proposal. Requiring a relative change in score makes the tag somewhat less luck-based and encourages the positive behaviour in more situations.

(The badge also the unique attribute that it is already in use in a different form. We can look at how often the hat was awarded for an idea of how often the badge would be, and to some extent (despite the hat being "secret") we see if people try to game it too badly.)

My first thought was that this encourages people to edit and then upvote crappy posts, or posts that wouldn't normally deserve an upvote. I kind of wish the requirements of hats were secret - it would be more fun and less likely to affect user behavior in any specific way.
– user159834Dec 19 '12 at 19:08

2

I don't agree with the duplicate. They're very similar (and there are other similar existing requests), but this one is a bit different and has the unique attribute that it is already in use in a different form. We can look at how often the hat was awarded for an idea of how often the badge would be, and (to some degree, despite the hat being "secret") see if people try to game it too badly. This criteria may also be better than the one in the other question: if a post is below -1 or -2 it's very hard to get it positive again; a relative improvement is more consistently achievable.
– GuestDec 19 '12 at 19:55

Note that the cake hat, as currently implemented, is trivial to acquire, especially if you frequently edit your own posts. To make it into a meaningful badge, there would have to be some indication that the post wasn't going to earn those five upvotes anyway. Maybe make it require that the post had a negative score when it was edited?
– Ilmari KaronenDec 27 '12 at 22:28

Those are basically my concerns. Go through Jon Skeet's answers, find one a year old, make a trivial edit, profit. I'm more for 0 or 1 score 'meh' answers .. why didn't they get more votes? Make them more awesome, and get the badge. The problems we're currently facing with bad reviewers just trying to get a badge more than illustrates that this would happen in reality.
– Tim Post♦Dec 20 '12 at 1:36

The behaviour that this badge should encourage (in my opinion) is to edit correct-but-badly-formatted (or typo-ridden) answers which would lead to them getting upvotes.

Unfortunately I think that this is not easiest way to get the hat (and the possible badge). The easiest way is almost certainly to do a minor edit to an already-good answer before it gets tons of votes.

That's would be the only drawback I see to making this a badge: people will game it.

People game all the badges (or at least they try to). You could make the criteria a "meaningful" edit where that's determined by the % of the post you edit. An already good answer you tweak to correct a typo would have a low % whereas one you reformat and perform wholesale spelling and grammar corrections would have a high %
– ChrisF♦Dec 20 '12 at 11:25

@gnat: I don't think that would work, at lorem ipsum would not cause the post to be upvoted (unless it was hidden inside tags or something similarly invisible). Maybe raising the bar high enough is enough here: as long as there are more-easily-gamed badges, it should be safe.
– Joachim SauerDec 20 '12 at 11:49

1

@gnat - You're right (as usual). The more I think about this the more I think I may have to retract my implicit support for this idea.
– ChrisF♦Dec 20 '12 at 11:49

@JoachimSauer it'll be invisible if enclosed in <!-- Lorem... --> - which would make it less harmful of course. But the real problem would be when gamers will add truly innocent looking garbage that's harder to catch as abuse than easily recognizable "Lorem ipsum"
– gnatDec 20 '12 at 11:56

...overquoting API javadocs is one example of gaming I am thinking about. It will look 200% innocent... but in the same time it could be actively harmful when essential, brief quotes are replaced with wall of text serving only the purpose of pumping edit percentage, right?
– gnatDec 20 '12 at 12:16

Couple of considerations to ensure that badge like that is awarded fairly.

It should not be awarded to posts that are proven to be going well without editing.

For example, as an editor I would find it embarrassing if I was awarded badge for an edit done here.

This basically means posts with sufficiently good positive score are not eligible.
It would be likely safe to consider posts with non-positive score, or maybe with score less than 3. The downside is this sort of closes the opportunity to reward edits that made +100 of a +10 post, but I for one could live with that.

It should not be awarded for posts having good chance to go well without editing.

Posts at the top of hot-questions all have good chances to get their portion of cheap populist upvotes without editing; as an editor I would be embarrassed to get a badge for an edit that easily.

This means only posts with score proven to be sufficiently stabilized are eligible.
Given bounty requirements, I'd say these are posts having no score changes for 2 days at least.

It should not be awarded for "co-located" edits.

If someone else does a badge-worthy edit that bumps the post, I would be embarrassed to get a badge for subsequent spotting and fixing of a minor typo there.

Safe way would probably be to allow only one badge per post.
This would definitely prevent awarding badges for co-located edits. On a downside, this would introduce a chance for somewhat unfair awards in cases when really great edit follows the bump caused by some minor change but I for one could live with that.

Regarding eligibility of edits done to own posts, consistency considerations should be taken into account when deciding on this, namely the fact that current editing-badges ignore such edits.

I would also consider establishing a line of badges instead of a single one. Graded by the amount of eligible edits done by a user, it would incentivize persistence in making edits valued by community.

A single rocket jump edit may happen by a pure chance, eg as a result of a luckily co-located change as mentioned above. As such, it hardly deserves more than a bronze badge.

A bunch of 5-10 eligible edits is a good indication of an editor being consistent hit maker, probably worthy of a higher (silver) recognition.

Finally, an outstanding stream of, say, 50-100 successful edits suggests somewhat of a pulitzer scale achievement, if one takes into account the sheer amount of upvotes it presumably triggered (50*5=250 at the very least, more than amount required for a golden great question / answer badge).

I don't agree. If you make an improvement on a post that then is substantial enough to get it more upvotes, why should you not get the badge? Are you not improving content? What difference does it make what user created the post? As always, the emphasis should be on content and not users.
– LixDec 27 '12 at 18:35

2

I made the post, there were some comments, I updated it to reflect those, and upvotes continued to come in. I don't think that's at all the same as fixing a crummy post into something worthy of upvotes
– Kate GregoryDec 27 '12 at 18:37

I already see too many minor edits in the edit review queue, obviously made by users hunting for two reputation points. The main reasons there isn't more of them might be that old reputation hunters can't get those two points.

I wouldn't want to also see many minor edits of new questions seeming promising.

Too many minor edits aren't painful just for reviewer, they're also painful for people making good edits which are prevented due to other ones.

We have enough editing in my opinion, and enough reasons to edit, we don't need that.

Damn... I made a gravatar image just for the cake I have on SO and it really doesn't fit on meta... I need to edit a promising post fast... :\
– Denys SéguretDec 20 '12 at 10:57

Darn ... I felt tempted to fix the "szz" in a minor edit, but you were faster.
– Joachim SauerDec 20 '12 at 10:57

I'm sure you'll see something else to edit, as I know my English is very poor (yes, the 'z' is near the 'e' on my keyboard, which means it's not qwerty)... Don't forget to also upvote my answer 5 times :)
– Denys SéguretDec 20 '12 at 10:58